Boris Johnson said a Queen’s Speech would take place after the suspension, on 14 October, to outline his “very exciting agenda”.
But it means the time MPs have to pass laws to stop a no-deal Brexit on 31 October would be cut.
House of Commons Speaker John Bercow said it was a “constitutional outrage”.
The speaker, who does not traditionally comment on political announcements, continued: “However it is dressed up, it is blindingly obvious that the purpose of [suspending Parliament] now would be to stop [MPs] debating Brexit and performing its duty in shaping a course for the country.”
It would be “an offence against the democratic process and the rights of Parliamentarians as the people’s elected representatives”, he added.